Monitoring and identifying changes to heating ventilation and air conditioning (hvac) conditions

ABSTRACT

An application for monitoring heating ventilation and air conditioning (HVAC) may include receiving, at a server, sensor signals from sensors disposed within a heating ventilation and air conditioning (HVAC) system, receiving, at the server, one or more HVAC control signals indicating one or more currently active control functions assigned by an HVAC controller, comparing a threshold value to one or more of the plurality of measured sensor values, determining, via the server, based on the one or more currently active control functions that a current condition level of the HVAC system is less than a threshold value, and generating, via the server, an alert to identify the current condition level as a potential failure.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application No. 63/396,202, filed on Aug. 8, 2022, the disclosure of which is hereby incorporated by reference in its entirety.

FIELD OF INVENTION

The present invention relates to remote monitoring and more particularly to monitoring and identifying changes to heating ventilation and air conditioning (HVAC) conditions.

BACKGROUND OF THE INVENTION

Conventionally, a heating ventilation and air-conditioning (HVAC) system operates each day in a person's home or place of business to provide heat, air flow and cooling air (air-conditioning) throughout a particular environment. The problems that arise with such systems are almost entirely identified through testing and investigation and often reveal failed hardware that requires immediate replacement and inevitable downtime with no HVAC operation.

Testing such HVAC equipment by a trained professional requires time and the expertise of the trained professional which could be spent on other tasks. With a shortage of such professionals throughout the world, there is a low likelihood of affordable maintenance and testing being performed on most HVAC system prior to a problem arising.

III. SUMMARY OF THE INVENTION

Example embodiments of the present application disclose hardware, software and/or operations and procedures configured to provide wireless communication signals comprising updates from a plurality of sensors placed within the HVAC system, determining a HVAC system is experiencing a failure, and generating an alert to identify the failure or inefficiency.

One example process may include an application for monitoring heating ventilation and air conditioning (HVAC) may include receiving, at a server, sensor signals from sensors disposed within a heating ventilation and air conditioning (HVAC) system, receiving, at the server, one or more HVAC control signals indicating one or more currently active control functions assigned by an HVAC controller, comparing a threshold value to one or more of the plurality of measured sensor values, determining, via the server, based on the one or more currently active control functions that a current condition level of the HVAC system is less than a threshold value, and generating, via the server, an alert to identify the current condition level as a potential failure.

IV. BRIEF DESCRIPTION OF THE DRAWING(S)

FIG. 1 illustrates a conventional HVAC controller.

FIG. 2 illustrates a HVAC application control network according to example embodiments.

FIG. 3 illustrates a graphical user interface HVAC application operating on an end user device according to example embodiments.

FIG. 4A illustrates an exemplary sensor feedback configuration for detecting temperature difference across HVAC components according to example embodiments.

FIG. 4B illustrates an exemplary sensor feedback configuration for detecting a fault with the fan portion of the HVAC system according to example embodiments.

FIG. 4C illustrates an exemplary sensor feedback configuration for detecting an unwarranted heater operation with the HVAC system according to example embodiments.

FIG. 4D illustrates an exemplary sensor feedback configuration for detecting a frozen cooling coil in the HVAC system according to example embodiments.

FIG. 4E illustrates an exemplary sensor feedback configuration for detecting an abnormal humidity condition in the HVAC system according to example embodiments.

FIG. 5 illustrates an example graphical user interface of a HVAC application control interface according to example embodiments.

FIG. 6 illustrates an example flow diagram of an example process according to example embodiments.

FIG. 7 illustrates an example network entity device configured to store instructions, software, and corresponding hardware for executing the same, according to example embodiments.

V. DETAILED DESCRIPTION OF THE EMBODIMENT(S)

Example embodiments provide a remote monitoring application and diagnosis system for HVAC systems which includes capturing data from an ‘HVAC’ or ‘air conditioning’ system, hereinafter the terms are used interchangeably, and sending the locally captured sensor information via a wireless communication signal to a local access point (e.g., Wi-Fi router, cellular communication tower, etc.), which forwards the information to a HVAC application server (e.g., cloud server), which distributes the information to subscribers, such as a mobile device of a technician subscribed to the receive such information, a neighborhood representative (e.g., homeowner management company), a home owner and/or other interested parties, such as a service provider HVAC corporation that is contracted to monitor such information for potential faults. The application on the server and/or the end user devices (e.g., smartphones, laptops, tablets, office computer, etc.), may have an application that audits the data based on thresholds of temperature, humidity, voltage, current, moisture, etc., to identify a likely fault, such as heating, cooling, fan operation, power outage, etc.

Alerts can be generated based on certain realized information. For example, a set of sensors which detect noise, moisture, pressure, temperature, electrical properties (e.g., conductivity, current, voltage, etc.), may be affixed to the HVAC operational unit, such as an indoor portion (air handler, fan) and/or to the outdoor portion (exchanger, condenser/coil), and periodic sensor data may be captured and shared with the computer system of the server so logic can be employed to determine the potential failures (e.g., thresholds, unexpected sensor data, etc.). The subscribers may have an application that periodically receives updates and alerts from the server system in the cloud. Alerts may include emails, application notifications, text messages, etc., which can be employed to notify the customer, technician or other party of the potential failure concern.

The notification(s) may be created and sent to various users by text, an application notification, an e-mail and/or phone call. A user may elect a specific type of data combination which will cause an alert to be activated, such as a specific temperature threshold and/or a specific temperature different (ΔT). A HVAC technician can access and view the current status and past history of the entire AC system. The data monitoring and collecting devices may be installed at an indoor and/or outdoor portion of the AC system. Data obtained from the temperature/humidity sensors, current sensors, and other sensors, and signals, such as ‘T-stat’ signals (e.g., yellow, white, red, green, orange, etc., control lines), current status, and power status, and the information may be sent to a remote server from the sensors installed on the HVAC system which provide wireless communication data to the Wi-Fi in a user's home or workplace. The system may further include a cellular module, a Wi-Fi module, etc., and other communication controls which are part of a circuit board that includes such modules and memory, a processor, alert indicators, sensors, communications ports, etc.

The monitoring and diagnosis application system for heating, ventilation and air conditioning (HVAC) systems includes a remote server communicating with one or more HVAC systems via a wired or wireless network, a user portal (e.g., a mobile phone application, a program, a web page, and/or other software interface) on a hardware interface configured via a remote server controller, a communications port for sending and/or receiving data related to operation of one or more HVAC system controllers of the one or more HVAC systems, a memory for storing information comprising data related to the operation of one or more HVAC system controllers, a processor operatively coupled to the communications port and the memory, wherein the processor is configured to analyze data received related to operation of the one or more HVAC systems, a plurality of HVAC system component sensors, user-defined parameters (based upon user-defined data and data combinations) causing alerts to be activated and transmitted to user(s) (such as via a text or e-mail message), and the alerts may also include a plurality of options, such as colored alert indicators (red, yellow, green, etc.) signaling an active HVAC condition exists with respect to the one or more HVAC systems, such that a particular color of the indicator/alert corresponds to the likely underlying issue or malfunction, thereby enabling the user of the system to both immediately identify the specific issue causing the alert and provide a suggested solution. The alerts may be based on thresholds which are near their peak values and/or which have been exceeded or underperformed.

FIG. 1 illustrates a conventional HVAC controller. The example 100 includes a HVAC control board hard wired to a controller and/or thermostat portion to trigger certain controls based on temperature and settings. The red (R) line is a control for a voltage power, such as 24 VAC power, the yellow line (Y) turns on the cooling, the white line (W) turns on the heat, the green line (G) turns on the fan and the common line (C) turns on the power, such as 24 VAC for common, (O) turns on a position of a reversing valve which may change seasonally. The wires can be tapped to identify controls, for example, the state of the thermostat may be no signal for a wire=0 and a signal present for wire=1. The temperature, current and air pressure can all be sensed by sensors to determine if the equipment is operating correctly. In one example, the temperature sensors may read the return and supply temperatures of the system to determine if the temperature drop or difference across the coil (ΔT) is what is expected. In one example, the ΔT should be 15 degrees difference. The number may be adjusted depending on the environment or geographical location since the ΔT in one part of the country may be different from the ΔT in another part of the country. When the ΔT is not at least a threshold value, such as 15 degrees or more, then there may be an alert generated which is received by the HVAC technician who is operating an application that receives the data periodically and especially when there is a condition detected that is not within the range of expected results.

In another example, the current sensor can be used to determine whether the blower is operating and whether one or more controls are working. For example, when the blower is sensed via the current sensor and the heating or cooling is not operating and it should be based on a temperature reading, then an alert may be generated. The air pressure sensor can be used to identify whether air is moving through the duct work. With the temperature ΔT example, if the sensors are inside the duct work in two places, such as sensor 1 (S1) which is inside the portion of the duct work where it should be cool and the second sensor 2 (S2) is inside the duct work where it should be warmer, an ideal temperature may be a ΔT of 20 degrees or at least 15 degrees and anything less indicates a potential problem so an alert can be created (see FIG. 4 ). With current sensing, the main power line, with less than 1 ampere (AMP), the blower and heaters may not be running, with more than 1 AMP but less than 5 AMPs the blower is determined to be running, if 20 AMPs or more are detected, then heat is believed to be operating. Certain sensors, such as pressure, temperature, noise sensors, etc., can also assist with confirming the correct operation of the HVAC system. Any data detected can be sent via a wireless communication signal or a wired signal to a home based router or communication access point and/or a cellular communication tower to report the data to the remote server.

FIG. 2 illustrates a HVAC application control network according to example embodiments. Referring to FIG. 2 , the large-scale system 200 includes a HVAC system 220 with indoor components 222, outdoor components 224, a HVAC communication control board 226 and the existing HVAC controller/thermostat 228. The system sensors 230 can continually monitor the system attributes. The signals from the thermostat (T-stat) 242, the return temperature and humidity 244, the AC current 246, the supply temperature 248 and the level of pressure 249 can all be used to perform basic troubleshooting without a technician present. Data can be continually shared with the wireless communication site 250 via the control board 226 via a wireless communication chip or board. The data can be sent to the application server 260 where the software application operates to provide alerts, user interfaces and demonstrate unacceptable and acceptable sensor readings based on software specified anomalies including but not limited to a threshold range reading for any of the sensors or combinations of sensors. The end user device 270 may receive updates on the user device and alerts for both acceptable and unacceptable usage.

FIG. 3 illustrates a graphical user interface HVAC application operating on an end user device according to example embodiments. Referring to FIG. 3 , the example 300 includes two example scenarios which are likely to occur when there is a problem. In the example 352, a user device 310 may demonstrate that the ΔT is not at least the threshold amount of ΔT (e.g., 20, 15 degrees, etc.). The second example 354 demonstrates that the current is sensed but the controller signal has not been able to launch the heating or cooling air via another sensor. This may also be a common problem requiring an alert, such as “air only at this time”.

FIG. 4A illustrates one exemplary sensor feedback configuration 400 according to example embodiments. Referring to FIG. 4A, the HVAC system 410 may have sensors measuring air temperature inside the duct work to provide a first sensor (S1) temperature reading 422 and a second sensor (S2) temperature reading 424 to help identify the ΔT. When the ΔT is not large enough, the system may have a problem cooling. Although, other examples can be demonstrated and cause alerts to be generated. The sensors in this example can measure information between the air flow return side 412 of the cooling coil 410 and after on the air flow supply side 414 as the air comes into and out of the air cooling unit. The information may be transferred via wired or wireless signals to the HVAC communication and control board 226 which may be an installed device that has the capability to share the data to a remote server across the Internet through the Wi-Fi access device operating near the HVAC system or via a wired connection, such as a phone line, Ethernet interface, or even a cellular communication network that is operating within the area of the control board 226. Another option would be to relay the information to a user device, such as a smartphone and have that device share the information with the server responsible for compiling the data. The server may be a computer near the area of the HVAC system, a smartphone, a cloud server, or just a basic computing device included as part of the HVAC control board 226.

The data collected may include a device ID, a signal strength, a time, date, a temperature T1, T2 . . . T_(N), temperatures, a humidity level H1, H2 . . . H_(N) humidity levels, amperes (AMPs), signals from the thermostat (Tstat) including which components are on and off, power on/off, etc. A set of data can be shared every minute, 5 minutes, etc. More information can be shared while the system is on and fewer information messages can be sent when the system is off. Also, a request can be received and processed to send data when a request is received by the application circuit board by the application sent from the user device 310. The HVAC communication control board may receive signals from the sensors constantly once per minute or other defined period of time. The change in temperature ΔT may be computed after the HVAC system has been operating for a certain period of time, such as “N” minutes or more. Also, an ideal threshold may be selected for a particular HVAC system based on the type of system, the area the system is located, etc. For example, the ΔT in Portland Maine may be different from the ΔT in Baton Rouge Louisiana as relative temperatures for such measurements during summer months will vary based on climate. The input from the controller may also be necessary to compile the proper diagnosis and alerts. The controller input 428 may indicate which controls are on and thus which function is being used. In general, the Y and G signals indicate cooling air or air conditioning. The Y and G signals may trigger the control board to compile the ΔT information based on the control signals received. Other control signals from the control unit 100 may cause different thresholds and sensor data to be used for other types of measurements and diagnoses. A user or administrator may create any threshold value for any particular sensor or combination of sensors to ensure the ongoing monitoring is performed according to local standards and preferred operation standards. Also, the customization of the monitoring application may include monitoring specific sensors disposed within the HVAC system while omitting data from other sensors depending on the control signals received and including any other parameters which are deemed relevant for monitoring purposes.

FIG. 4B illustrates an exemplary sensor feedback configuration for detecting a fault with the fan portion of the HVAC system according to example embodiments. Referring to FIG. 4B, the configuration 430 includes an electromagnetic sensor S3 406 providing a current measurement via an electromagnetic reading on the power supply line of the power supply 408. The blower/fan 416 in this example may be identified as not being operational. For example, the ΔT may be measured by the sensors 402 and 404 and the control unit 100 may indicate that the system is cooling via the yellow and green signals, however, the sensor S3 may indicate that an amount of amperes measured may be indicative of the fan 416 not actually working or drawing any current from the power supply 408. The cooling system may use ½ to approximately 4 amps, however, the fan 416 may require additional amps which are not detected by the sensor S3 406. Also, the ΔT may be less than expected as well or below the threshold value expected, such as 16 degrees Fahrenheit. Using the temperature sensor(s) and the current sensor S3 together as different types of sensors may cause the diagnosis to be that the cooling system is working, the ΔT is below the threshold and the fan 408 is not working and is the cause of failure. The server may receive this data and provide an alert to the interested parties registered to receive the data. The example in FIG. 4B may also indicate that the heater is not operating properly when the amperes are low 426 and a white signal is present (not shown) by the controller 100.

It is important to note that any of the examples of FIGS. 4A through 4E may be combined into one or more scenarios for indicating a failure. The examples of FIGS. 4A through 4E are not intended to be separate exclusive examples of measurements being conducted.

FIG. 4C illustrates an exemplary sensor feedback configuration for detecting an unwarranted heater operation with the HVAC system according to example embodiments. Referring to FIG. 4C, the example configuration 440 may indicate that the heater is operating and the circuit controller 100 may not be able to control the operation of the system. When the yellow signal and the green signal are identified, the system should be cooling. The ΔT value may be low if the heat is triggered by a failure in the control system. The current sensor S3 will identify a large amount of current 432 being used, such as over 20 amps even though the system is set to use air conditioning only. The failure may be in the heater circuit, heater components and/or the heating element(s) and even with the heating controls, such as a relay or other component. When heat is identified based on a combination of the temperature sensors S1 and S2 and/or the current sensor S3, the system may yield a red alert indicating action should be taken to correct the erroneous heat being produced.

FIG. 4D illustrates an exemplary sensor feedback configuration for detecting a frozen cooling coil in the HVAC system according to example embodiments. Referring to FIG. 4D, the configuration 450 provides a diagnosis of a collapsed ductwork and/or a frozen coil. The cooling coil may have additional temperature sensors S4 407 and S5 409 which measure the liquid line and the suction line, respectively. In this example, the suction line sensor S5 409 may indicate a temperature which is very low. The inputs received 443 and 445 from S4 and S5 may indicate extreme cold, such as close to or below 32 degrees Fahrenheit at the suction line sensor S5 409. The diagnosis may include a collapsed or congested air flow situation brought about by a collapsed air vent and/or via a dirty filter which does not allow enough air to pass per unit of time. Such a condition(s) may cause a freeze to occur in the cooling coil lines which can be detected by the temperature sensors on the coil components. An ideal threshold value for the coil components may be 40-55 degrees Fahrenheit, and if the temperature of the sensors indicates a value closer to freezing then the coil is likely experiencing a freezing condition or soon to be frozen, which can result in an alert being generated and sent to the interested parties to perform a checkup service. Another example may include tracking the liquid line temperature via the sensor S4 407 and determining whether the outside temperature is approximately 25 degrees Fahrenheit different than the liquid line temperature during warm summer months. A threshold of 20 or 30 degrees may be established to trigger an alert when the change in temperature between outside and the liquid line temperature exceeds that threshold difference.

FIG. 4E illustrates an exemplary sensor feedback configuration for detecting an abnormal humidity condition in the HVAC system according to example embodiments. Referring to FIG. 4E, the example configuration 460 provides an example of a high humidity condition measured by a humidity sensor S6 411 which can be near or inside of the ductwork of the HVAC system. The humidity level may have a threshold value of 65% to 75% and if the measured humidity is higher than that value, there may be a duct work failure that is returning air from an untreated area, such as an attic or crawlspace, or there may be an unexpected amount of moisture that is causing moisture to increase within the HVAC system and/or that is causing moisture to accumulate near the HVAC system. The humidity sensor S6 411 may be used as an additional basis to cross-reference other conditions as well, similar to the current sensor S3 406. Also, a lack of a yellow signal may indicate that cooling is not actively occurring when it should be occurring as an additional condition to create an alert to interested parties.

FIG. 5 illustrates an example graphical user interface of a HVAC application control interface according to example embodiments. Referring to FIG. 5 , the example user interface 500 includes a log of sensor data for a particular day at any such locations registered and regularly monitored. The sensor data 510 may be timestamped with time, date, location, ΔT, humidity, current, and a result which is a function of one or more of the sensor data and control unit components. The diagnosis criteria may be default or customized by the HVAC technicians using the application to monitor customer sites. Threshold values may be set manually and used as a basis for future alerts based on the sensor data and/or the control unit status conditions. The area of interest may be displayed on a map 514 to provide technicians with a snapshot of locations to plan maintenance actions for a particular day or period of time. The alerts may be displayed 512 in a separate menu to show green, yellow and red alerts depending on the system configuration. Sensor data history 516 may be available to show previous readings to help technicians identify the results of neighbors and to reduce false positives.

FIG. 6 illustrates an example flow diagram of an example process according to example embodiments. Referring to FIG. 6 , the example process may include receiving, at a server, a plurality of sensor signals from a plurality of sensors disposed within a heating ventilation and air conditioning (HVAC) system 612. The sensor data may be from various sensors disposed adjacent to the HVAC system, inside the ductwork of the HVAC system, and/or on components of the HVAC system. The process may also include receiving, at the server, one or more HVAC control signals indicating one or more currently active control functions assigned by an HVAC controller 614. The control signals may be a status of the various control lines of the controller 100 to provide current status, which may be used to retrieve one or more thresholds to compare to the sensor measurements based on the control signals received. For example, if the cooling control signal is present, the ΔT measurement threshold may be used to compare to the sensor data of the temperature sensors. The process may also include comparing a threshold value to one or more of the plurality of measured sensor values 616 and determining, via the server, based on the one or more currently active control functions that a current condition level of the HVAC system is less than a threshold value 618, and generating, via the server, an alert to identify the current condition level as a potential failure.

In one example, the plurality of sensor signals may include a respective plurality of sensor values measured a plurality of times over a defined time period. For instance, the sensor signals may need to be measured three times over one minute and an average is taken to reduce false positives. The plurality of sensors may include a first temperature sensor and a second temperature sensor, and the first temperature sensor may be disposed in an air flow duct between an air flow return side and a cooling coil, and the second temperature sensor may be disposed in an air flow duct between the cooling coil and an air flow supply side. The process may also include determining a difference in temperature between the first temperature sensor and the second temperature sensor is below the threshold value. In one example, a yellow controller signal (cooling) may initiate a start of a timer that is used as the basis for a period of time that can be applied as a defined time period. In one example, the yellow signal being detected at an initial time, the period of time, such as ‘N’ minutes later may be required to perform an accurate temperature difference (ΔT) measurement or other type of measurement. Any of the signals provided by the HVAC controller may initiate the beginning of a time interval required to perform an accurate sensor measurement.

The process may also include determining the HVAC system has been performing a cooling or heating operation for a predetermined period of time, such as ‘N’ minutes, and performing the comparing of the threshold value to the one or more of the plurality of measured sensor values after the HVAC system has been performing the cooling or heating operation for the predetermined period of time. The process may also include determining the threshold value to use for the comparison based on the one or more currently active control functions of the HVAC controller, such as heating, cooling, fan, etc. The plurality of sensors may include a first temperature sensor and a second temperature sensor, and the first temperature sensor is disposed on a liquid line inside a cooling coil and the second temperature sensor is disposed on a suction line of the cooling coil. The plurality of sensors may include an electromagnetic sensor disposed on a power supply line of the HVAC system and a humidity sensor disposed adjacent to the HVAC system.

The operations of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a computer program executed by a processor, or in a combination of the two. A computer program may be embodied on a computer readable medium, such as a storage medium. For example, a computer program may reside in random access memory (“RAM”), flash memory, read-only memory (“ROM”), erasable programmable read-only memory (“EPROM”), electrically erasable programmable read-only memory (“EEPROM”), registers, hard disk, a removable disk, a compact disk read-only memory (“CD-ROM”), or any other form of storage medium known in the art.

An exemplary storage medium may be coupled to the processor such that the processor may read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an application specific integrated circuit (“ASIC”). In the alternative, the processor and the storage medium may reside as discrete components. For example FIG. 7 illustrates an example network element 700, which may represent any of the above-described network components.

As illustrated in FIG. 7 , a memory 710 and a processor 720 may be discrete components of the network entity 700 that are used to execute an application or set of operations. The application may be coded in software in a computer language understood by the processor 720, and stored in a computer readable medium, such as, the memory 710. The computer readable medium may be a non-transitory computer readable medium that includes tangible hardware components in addition to software stored in memory. Furthermore, a software module 730 may be another discrete entity that is part of the network entity 700, and which contains software instructions that may be executed by the processor 720. In addition to the above noted components of the network entity 700, the network entity 700 may also have a transmitter and receiver pair configured to receive and transmit communication signals (not shown).

Although an exemplary embodiment of the system, method, and computer readable medium of the present invention has been illustrated in the accompanied drawings and described in the foregoing detailed description, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions without departing from the spirit or scope of the invention as set forth and defined by the following claims. For example, the capabilities of the systems described can be performed by one or more of the modules or components described herein or in a distributed architecture. For example, all or part of the functionality performed by the individual modules, may be performed by one or more of these modules. Further, the functionality described herein may be performed at various times and in relation to various events, internal or external to the modules or components. Also, the information sent between various modules can be sent between the modules via at least one of: a data network, the Internet, a voice network, an Internet Protocol network, a wireless device, a wired device and/or via plurality of protocols. Also, the messages sent or received by any of the modules may be sent or received directly and/or via one or more of the other modules.

While preferred embodiments of the present application have been described, it is to be understood that the embodiments described are illustrative only and the scope of the application is to be defined solely by the appended claims when considered with a full range of equivalents and modifications (e.g., protocols, hardware devices, software platforms etc.) thereto. 

What is claimed is:
 1. A method comprising: receiving, at a server, a plurality of sensor signals from a plurality of sensors disposed within a heating ventilation and air conditioning (HVAC) system; receiving, at the server, one or more HVAC control signals indicating one or more currently active control functions assigned by an HVAC controller; comparing a threshold value to one or more of the plurality of measured sensor values; determining, via the server, based on the one or more currently active control functions that a current condition level of the HVAC system is less than a threshold value; and generating, via the server, an alert to identify the current condition level as a potential failure.
 2. The method of claim 1, wherein the plurality of sensor signals comprises a respective plurality of sensor values measured a plurality of times over a defined time period.
 3. The method of claim 1, wherein the plurality of sensors comprises a first temperature sensor and a second temperature sensor, and wherein the first temperature sensor is disposed in an air flow duct between an air flow return side and a cooling coil, and wherein the second temperature sensor is disposed in an air flow duct between the cooling coil and an air flow supply side.
 4. The method of claim 3, comprising determining a difference in temperature between the first temperature sensor and the second temperature sensor is below the threshold value.
 5. The method of claim 1, comprising determining the HVAC system has been performing a cooling or heating operation for a predetermined period of time; and performing the comparing of the threshold value to the one or more of the plurality of measured sensor values after the HVAC system has been performing the cooling or heating operation for the predetermined period of time.
 6. The method of claim 1, comprising determining the threshold value to use for the comparison based on the one or more currently active control functions of the HVAC controller.
 7. The method of claim 1, wherein the plurality of sensors comprise a first temperature sensor and a second temperature sensor, and wherein the first temperature sensor is disposed on a liquid line inside a cooling coil and the second temperature sensor is disposed on a suction line of the cooling coil.
 8. The method of claim 1, wherein the plurality of sensors comprise an electromagnetic sensor disposed on a power supply line of the HVAC system and a humidity sensor disposed adjacent to the HVAC system.
 9. An apparatus comprising: a receiver configured to receive a plurality of sensor signals from a plurality of sensors disposed within a heating ventilation and air conditioning (HVAC) system; receive one or more HVAC control signals indicating one or more currently active control functions assigned by an HVAC controller; a processor configured to compare a threshold value to one or more of the plurality of measured sensor values; determine based on the one or more currently active control functions that a current condition level of the HVAC system is less than a threshold value; and generate an alert to identify the current condition level as a potential failure.
 10. The apparatus of claim 9, wherein the plurality of sensor signals comprise a respective plurality of sensor values measured a plurality of times over a defined time period.
 11. The apparatus of claim 9, wherein the plurality of sensors comprises a first temperature sensor and a second temperature sensor, and wherein the first temperature sensor is disposed in an air flow duct between an air flow return side and a cooling coil, and wherein the second temperature sensor is disposed in an air flow duct between the cooling coil and an air flow supply side.
 12. The apparatus of claim 11, wherein the processor is further configured to determine a difference in temperature between the first temperature sensor and the second temperature sensor is below the threshold value.
 13. The apparatus of claim 9, wherein the processor is further configured to determine the HVAC system has been performing a cooling or heating operation for a predetermined period of time, and perform the comparison of the threshold value to the one or more of the plurality of measured sensor values after the HVAC system has been performing the cooling or heating operation for the predetermined period of time.
 14. The apparatus of claim 9, wherein the processor is further configured to determine the threshold value to use for the comparison based on the one or more currently active control functions of the HVAC controller.
 15. The apparatus of claim 9, wherein the plurality of sensors comprises a first temperature sensor and a second temperature sensor, and wherein the first temperature sensor is disposed on a liquid line inside a cooling coil and the second temperature sensor is disposed on a suction line of the cooling coil.
 16. The apparatus of claim 9, wherein the plurality of sensors comprise an electromagnetic sensor disposed on a power supply line of the HVAC system and a humidity sensor disposed adjacent to the HVAC system.
 17. A non-transitory computer readable storage medium configured to store instructions that when executed cause a processor to perform: receiving, at a server, a plurality of sensor signals from a plurality of sensors disposed within a heating ventilation and air conditioning (HVAC) system; receiving, at the server, one or more HVAC control signals indicating one or more currently active control functions assigned by an HVAC controller; comparing a threshold value to one or more of the plurality of measured sensor values; determining, via the server, based on the one or more currently active control functions that a current condition level of the HVAC system is less than a threshold value; and generating, via the server, an alert to identify the current condition level as a potential failure.
 18. The non-transitory computer readable storage medium of claim 17, wherein the plurality of sensor signals comprises a respective plurality of sensor values measured a plurality of times over a defined time period.
 19. The non-transitory computer readable storage medium of claim 17, wherein the plurality of sensors comprises a first temperature sensor and a second temperature sensor, and wherein the first temperature sensor is disposed in an air flow duct between an air flow return side and a cooling coil, and wherein the second temperature sensor is disposed in an air flow duct between the cooling coil and an air flow supply side.
 20. The non-transitory computer readable storage medium of claim 19, wherein the processor is further configured to perform determining a difference in temperature between the first temperature sensor and the second temperature sensor is below the threshold value. 